While the heat is unusual in its magnitude, warmer winters in the U.S. are becoming the rule, not the exception. It’s the fastest-warming season for 37 states that roughly 220 million people call home.

Climate change is driving up the temperature around the year and around the globe, but topography, weather patterns and snow cover — among other factors — yield regional differences for warming.

In the U.S., that means winters are warming fastest from Montana to Florida, springs are cranking up the quickest in the Southwest, and falls are feeling the heat in the Northwest. Then there’s the Lone Star State as the lone place where summer is warming the fastest.

If you look at all four seasons across all of the Lower 48 states — for a grand total of 192 state-season combinations — there are only three instances of cooling. The Dakotas and Iowa are cooling ever so slightly in summer.

Otherwise, there’s only one direction temperatures have gone: up.

Snow cover in particular plays a role in why winters are heating up so fast from Montana to North Carolina. Or more specifically, it’s a lack thereof.

As temperatures rise, snow is decreasing — and in many cases being replaced by rain. Replacing light snow with dark ground means more of the sun’s energy is absorbed leading to a faster increase in warming.

Melting snow also represents a potential feedback loop that could send winter and spring temperatures soaring even higher. More dark ground is exposed as snow disappears, which leads to even more warming and more snow disappearing.

And in the Northwest, falls are heating up fastest since 1970. Research published in 2014 indicates that the increased seasonal warmth is likely driven by changes in the Pacific-North American pattern and El Niño, two climate oscillations that can have strong impacts on the region.

There will continue to be regional and seasonal differences in trends across the U.S. (and the world for that matter). Despite those differences, climate change will overwhelming contribute to rising temperatures in the coming years and decades, regardless of what season it is.

The calendar may have turned to 2016, but temperatures are picking up where 2015 left off. January was record warm, according to data released this week by NASA. You may recall that last year was the hottest on record for the globe. And by NASA’s accounting, it ended with a bang. This past December was the warmest December on record and the most

This week, parts of Oswego County in New York got a stunning 3 feet of lake effect snow. It was a rare event for a February and one that can be pinned to near “rock bottom” ice cover on the Great Lakes, as one scientist put it. Ice cover on the lakes stood at a mere 12 percent as of Feb. 11 (compared to 63 percent at the same time last year) thank

The snows are falling again across the East Coast, but up in parts of Alaska, snow has been a virtual no-show this winter thanks to extremely warm temperatures and weather patterns that have kept storms away. With temperatures expected to stay warm through February, concerns over the potential impact on the coming wildfire season are rising. Both

In many locations across the country, the snow season is getting shorter, with less snow at the beginning and the end. These changes in winter snowfall have economic, recreational, and environmental consequences. Even in a warming world, snow will fall. However, the amount of snow and when it falls will likely change as greenhouse gases build up in